The Renewables Working Group has not met for some time, possibly due to other priorities and the changing nature of the Trust and it volunteers. Below are some of the projects we have looked it the past. If you would like to propose new ideas and be part of the group or you have any questions, please contact Andy on this link.
Solar at Cultybraggan
The 10 kW of Solar Photovoltaic panels installed on Wild thyme’s building in 2010 has generated 6,000 KWh KWh per annum. It was estimated that they would produce 7500 KWh per annum so they are running at about 80% efficiency. This will provide a Feed in Tariff income of around £2,570.
The Camp (excluding Bunker) used 140,842 KWh for Apr 12 – Mar 13. Assuming the 6,000 from solar for the year, total electricity use was 147,000 KWh, so solar last year was currently 4% of power used. And we can expect that to be 5% in an average year if we achieve the average 7,500 KWh per year.
Future Solar at Cultybraggan
The Renewables Working Group have been investigating the potential to increase solar power at the camp. Some ideas being explored are:
1) Increase array on Wild Thyme from 10 Kw to 30kW. This would cost in the region of £27,000, with a payback of 5.5 years and a 20 year income of £98,624
2) Install a 10 kW array on the site of the bunker. Costs and income to be confirmed.
3) Install up to 150 Kw array on a sloped roof constructed on the rifle range site. This would require a roof/frame to be constructed at additional cost but the installation itself would cost around £170,000 with a payback period of 12 years and the income over 25 years is estimated at £1,140,367.
4) Ground mounted arrays at various points around the camp and also on the sewage treatment site.
All of the above require substantial investment.
Community Woodfuel
Naomi Clarke visited Fintry Development Trust in September 2012. One of the renewable projects that they promote is a bulk woodfuel scheme whereby they buy bagged wood in bulk and sell it onto the community at a reduced rate. This sparked much discussion among the Cultybraggan Working Group and RWG about what potential there is in Comrie to do this. The heat from the DHS could also be used to either dry wood (using a purchased log drying kit) or to keep wood dry. Wood could be supplied from windfall of local estates and also Laggan Wood.
A meeting was organised with Forest Enterprise and various interested local community groups to discuss a partnership agreement for the management of the woodland. There were many different questions and ideas put forward and together with the fact that Forest Enterprise are looking for community input into their design planning process, led to the conclusion that a more detailed meeting was required. This will be in the form of Forestry Enterprise led walks around the woods followed by an open meeting to discuss and prioritise ideas.
This initiative is looking for renewed interest from the community.
Hydropower
RWG have spent considerable time investigating various hydropower possibilities for Comrie. Sadly the overall conclusion is that there are no suitable sites! In summary:
1) Drummond Fish Farm – The weir was thought to have potential, but the the fastest flow from the weir came from the opposite bank. This would involve very expensive and complicated civil engineering to harvest the hydro potential. A lade on the fish farm site, coming off the weir had some potential for an easier installation. James Buchan from CES looked at the flows and calculated a hydropower potential of 25kW from this lade. This would cost around £250,000 to develop. Over 20 years, income from this would just enable a loan to be paid off with very little revenue being raised. There would also be the approximate £400,000 purchase of the land to fund. If it was grant funded, FIT could not be sought and the scheme could only be used as electricity generation on site.
2) Hillground at Cultybraggan – Limited by SEPA to 10000 litres per day.
3) Town weir site – the legal costs and complications in finding all of the landowners involved was prohibitive and the suitability of the site was also in question from the feasibility studies.
